JPH0712546B2 - Resistance welder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes an upper electrode and a lower electrode, and a guide pin of the lower electrode is appropriately provided with a work and a projection welded portion (hereinafter, simply referred to as a welded portion) on the back side. Resistance welding in which a welding member such as a projection nut (hereinafter simply referred to as a nut) having through holes penetrating the front and back is set, and pressure is applied by the upper electrode from above to resistance weld the welding member to the work. Regarding the machine.

[0002]

2. Description of the Related Art Conventionally, in this type of resistance welding machine,
If the welded part is not placed on the work side as the direction of the supplied nut, welding failure will occur.Therefore, supply the nut feeder etc. so that the welded part of the nut is properly placed on the work side for welding. The device is used to feed the nut in a fixed direction.

However, in a state where the nut is turned upside down (the nut in this state is called a back nut, and a state in which the nut is placed in a normal posture is called a normal nut), for example, a normal nut has a welded portion placed on the lower surface side. In some cases, the welding portion may be arranged on the upper surface side and supplied, and in order to solve the problem, the conventional resistance welding machine of this type uses JP-B-60-37167 and JP-B-60-. The one described in Japanese Patent No. 37164 is known.

In the former (Japanese Utility Model Publication No. 60-37167), an auxiliary electrode is provided on the upper electrode, and when the supplied nut is a back nut, the welded part of the back nut is used as an auxiliary electrode. By welding, the back nut is not welded to the work.

In the latter (Japanese Utility Model Publication No. 60-37164), a recess is provided in the upper electrode so that the upper side of the normal nut can be fitted, and when the back nut is supplied,
Even if the nut is not fitted to the upper electrode because the welded part interferes and the upper electrode approaches the lower electrode, the distance between the upper and lower electrodes will be longer than that of a normal nut. The sensor detects the lengthened state and stops the welding operation.

[0006]

However, in the welding machine described in the former, after the back nut is welded to the auxiliary electrode, the auxiliary electrode is replaced or the welded back nut is removed from the auxiliary electrode. Must be repaired. Furthermore, an auxiliary electrode corresponding to a welding member such as a nut must be embedded in the upper electrode, which lacks versatility.

The latter welding machine can handle the case where the welded part of the nut projects from the outer periphery of the nut body, but the welded part does not project from the outer periphery of the nut body (hexagon of JIS.B1196). With nuts and the like), there is no difference in the mutual distance between the upper electrode and the lower electrode between the back nut and the normal nut, which cannot be dealt with. Furthermore, the upper electrode must be provided with a recess corresponding to a welding member such as a nut,
It lacks versatility.

The present invention is to solve the above-mentioned problems, and regardless of the shape of a welding member such as a nut, it is possible to easily weld only a welding member in a normal arrangement position to a work piece, which is versatile. It is intended to provide a high resistance welding machine.

[0009]

A resistance welding machine according to a first aspect of the present invention includes an upper electrode and a lower electrode, and a projection is provided on the upper surface and the back surface of a work set on a guide pin of the lower electrode. A welding member having a welded portion and a through hole penetrating the front and back is set from the back surface side, pressure is applied by the upper electrode from the front surface side of the welding member, and the welding member is resistance welded to the work. A resistance welding machine, wherein the lower electrode is fixed to a resistance welding machine main body by holding an electrode tip capable of abutting on the lower surface of the welding portion of the work and the electrode tip at the upper end, and A cylindrical electrode holder that displaces the guide pin downward is provided, and a sensor that can detect the movement of the guide pin below the guide pin is provided. A guide part that is shorter than the length of the through hole of the welding member and that penetrates the welding member below the guide part. A step portion capable of abutting on the peripheral edge of the hole, wherein the sensor inserts the through hole into the guide portion and causes the step portion to contact the peripheral edge of the through hole so that the guide pin is welded to the welding member. When the projection welding portion of the welding member is moved to the position of the first position where the projection welding portion of the welding member is brought into contact with the work, and thereafter, the projection welding portion is melted during welding and the welding member is the work. When moving to the position of the second position welded to, it is possible to detect the two-step movement of, and the control device detects the detection signals of the first and second positions of the sensor at substantially the same time. When you have knowledge, and,
When the detection signals of the first and second positions of the sensor are not input, it is determined that welding is not possible, an abnormal signal is output, and the welding operation is controlled to be stopped.

A second aspect of the resistance welding machine of the present invention comprises an upper electrode and a lower electrode, a projection welding portion on the back surface side, and a through hole penetrating through the front and back surfaces with respect to the guide pin of the lower electrode. The welding member provided is set with the back surface side being the upper surface side, and further, the work having a through hole through which the guide pin can be inserted is set on the upper surface of the welding member, and the work piece is provided from the upper surface side to the upper part. A resistance welding machine that pressurizes with an electrode to resistance-weld the welding member to the workpiece, wherein the lower electrode has an electrode tip capable of contacting the lower surface of the welding member, and the electrode tip at the upper end. A cylindrical electrode holder, which is held and fixed to the main body of the resistance welding machine, and in which the guide pin is movably arranged downward in the upper inner peripheral portion, and movement of the guide pin is detected below the guide pin. A possible sensor, wherein the guide pin is inserted through the electrode tip and protrudes upward from the electrode tip to be insertable into the through hole of the welding member, and is longer than the entire height of the welding member, and A guide part that is shorter than the total length of the welding member and the thickness of the workpiece, and a step part that can abut the peripheral edge of the through hole of the welding member at the lower part of the guide part, and the sensor is provided. The guide member is fitted into the through hole of the welding member and the step portion is brought into contact with the peripheral edge of the through hole of the welding member to set the welding member on the guide pin, and further on the upper surface of the welding member. Moving from the set position where the through hole of the work is inserted into the guide part and the work is set to the first position where the front surface side of the welding member is brought into contact with the upper surface of the electrode tip. When the, then, the projection welding portion is capable of detecting the movement of the two stages and when the welding member is melted is moved to the position of the second position which is welded to the workpiece, during welding,
The control device detects the detection signals of the first and second positions of the sensor substantially at the same time, and the first and second positions of the sensor.
When the two-position detection signal is not input, it is determined that welding is not possible, an abnormal signal is output, and the welding operation is controlled to be stopped.

[0011]

In the resistance welding machine according to the first aspect of the present invention, the work piece set on the guide pin of the lower electrode has a normal posture, that is, the welding portion is arranged on the lower surface side. As a result, when the welding member is set and the upper electrode is lowered in a posture in which the guide portion of the guide pin is fitted into the through hole and the peripheral edge of the through hole is brought into contact with the stepped portion of the guide pin, first, the welding is performed. The welded part of the member contacts the upper surface of the work,
The lowering of the guide pin is stopped.

Then, the sensor detects that the guide pin is arranged at the first position, and the control device which inputs the signal sends a welding current to the upper electrode and the lower electrode.

Thereafter, the welding current melts the welded portion, so that the guide pin descends together with the welding member.

Then, the sensor detects that the guide pin is arranged in the second position, and the control device which inputs the signal then raises the upper electrode, finishes the welding work, and then performs the next welding. Do the work.

When the welding member is turned over and set on the guide pin, or when the welding member is not set on the guide pin, there is no welded portion when the upper electrode descends, so that the guide pin moves to the first position. Immediately after that, the control pin is placed in the second position, or the guide pin is not placed in the first position. Therefore, the control device outputs an abnormal signal depending on the presence or absence of those signals from the sensor,
The welding work is stopped by raising the upper electrode.

Therefore, in the resistance welding machine according to the first aspect of the present invention, depending on the descending distance of the predetermined guide pin on the lower electrode side depending on the presence / absence of the welded portion of the welding member which is always present on the work side in normal condition. , Welding material supply status is normal /
This is for judging an abnormality, and unlike the conventional welding machine, it is not necessary to prepare an auxiliary electrode corresponding to the welding member or an upper electrode having a recess, and the welding portion projects from the outer periphery of the welding member main body. Even if the shape is not a shape, only the welding member in the normal arrangement position can be easily welded to the work, and the versatility can be improved.

In the resistance welding machine according to the second aspect of the present invention,
With respect to the guide pin of the lower electrode, in a normal posture, that is, with the welded part placed on the upper surface side, the guide part of the guide pin is inserted into the through hole, and the stepped part of the guide pin is contacted with the through hole peripheral edge. The welding member is set in the contacted position, and the work piece is set on the upper surface of the welding member by inserting the through hole into the guide portion of the guide pin. The surface side contacts the upper surface of the electrode tip, and the descent of the guide pin is stopped.

Then, the sensor detects that the guide pin is arranged at the first position, and the control device which inputs the signal thereof applies the welding current to the upper electrode and the lower electrode.

After that, since the welding portion is melted by the welding current, the guide pin is lowered together with the welding member.

Then, the sensor detects that the guide pin is arranged at the second position, and the control device which inputs the signal then raises the upper electrode, finishes the welding work, and then performs the next welding. Do the work.

Then, the welding member is turned over and set on the guide pin, or not set on the guide pin.
Further, when the work is not set, the guide pin is not arranged in the first position because the weld is arranged on the electrode tip side when the upper electrode is lowered, or Since the guide pin is placed in the second position immediately after passing through the first position, the control device outputs an abnormal signal depending on the presence or absence of those signals from the sensor, raises the upper electrode, etc.,
Stop welding work.

Therefore, in the resistance welding machine according to the second aspect of the present invention, similarly to the first resistance welding machine, the lower electrode associated with the presence / absence of the welded portion of the welding member which always exists on the work side in the normal state. This is to judge whether the supply condition of the welding member is normal or abnormal by the descending distance of the predetermined guide pin on the side, and like the conventional welding machine, the auxiliary electrode corresponding to the welding member and the upper electrode provided with the concave portion. It is not necessary to prepare, and even if the welded part does not have a shape protruding from the outer periphery of the main body of the welded member, only the welded member at the normal arrangement position can be easily welded to the work, improving versatility. You can

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The resistance welding machine M of the first embodiment shown in FIGS.
1 includes an upper electrode 2 and a lower electrode 3, and uses an air cylinder (not shown) or the like at a predetermined time for the upper electrode 2
Is provided with a control device 1 for bringing welding current to the upper and lower electrodes 2 and 3 by bringing them closer to the lower electrode 3.

The lower electrode 3 comprises an electrode tip 4, a guide pin 5, an electrode holder 6 and a sensor 21. The electrode holder 6 is fixed to a main body of a resistance welding machine (not shown) by using a bracket 22. The electrode tip 4, the guide pin 5, the sensor 21 and the like are held by the electrode holder 6.

The electrode tip 4 has its upper surface 4a brought into contact with the lower surface of the welded portion of the work 30, has a through hole 4b in the center thereof through which the main body 5a of the guide pin 5 can be inserted, and has a cylindrical sleeve portion at the lower portion. 4c, the male screw portion 4d formed on the outer peripheral surface of the sleeve portion 4c is screwed into the female screw portion 6a formed on the inner peripheral surface of the upper end of the electrode holder 6, and the electrode holder 6
Is located at the upper end of the.

The guide pin 5 includes a cylindrical main body 5a, a guide portion 5c extending upward from the upper portion of the main body 5a with a smaller diameter than the main body 5a, and a disc-shaped flange portion 5d having a larger outer diameter at the lower portion of the main body 5a. It is configured with. The guide portion 5c has an outer diameter that can be fitted into the through hole 31b of the nut 31 and has a total length shorter than the length of the through hole 31b. As for the outer diameter of the main body 5a, the step portion 5b on the guide portion 5c side can be brought into contact with the peripheral edge of the through hole 31b, and the step portion 5b is attached to the work 3
The size is such that it can be inserted into the zero through hole 30a.

A stopper ring is provided between the flange portion 5d of the guide pin 5 and the sleeve portion 4c of the electrode tip 4 so that a gap W can be dealt with even if the thickness t of the work 30 changes. A compression coil spring 7 is disposed between the stopper ring 8 and the peripheral edge of the through hole 4b on the lower surface side of the electrode tip 4. Coil spring 7
Is provided to prevent rattling of the guide pin 5.

The electrode holder 6 has a substantially cylindrical shape, and female screw portions 6a and 6c are formed on the inner peripheral surface of the distal end and the inner peripheral surface of the lower end, and the inner peripheral surface of the intermediate portion in the vertical direction has an inner diameter. A narrowed guide hole 6b is formed. In addition to holding the electrode tip 4, the electrode holder 6 has a detection rod 12 which extends slidably in the inner peripheral surface of the guide hole 6b and which extends vertically.

The detection rod 12 has a substantially cylindrical shape having a small diameter portion 12a, a large diameter portion 12b, and a small diameter portion 12c in order from the top, and transmits the lowering of the guide pin 5 to the lower sensor 21. The compression coil spring 14 whose lower end is held by the screw 16 is urged upward. The small-diameter portion 12a is provided with guide collars 9 and 11 provided with flange portions 9a and 11a, respectively.
A compression coil spring 10 is arranged between the flange portions 9a and 11a of 11. On the upper end surface of the large diameter portion 12b,
The lower surface of the flange portion 11a of the guide collar 11 abuts, and the lower end surface of the large diameter portion 12b is covered with a stopper ring 13 to which an upper end of a coil spring 14 abuts. Small diameter part 1
A rod stopper 18 made of a ring or the like is provided at the lower end of 2c.
Is provided.

The coil springs 7, 10 and 14 are configured so that the coil springs 10 have the largest urging force, the coil spring 14 has the largest urging force, and the coil spring 7 has the smallest urging force.

The regulation of the rising end of the detection rod 12 is as follows.
The rod stopper 18 is brought into contact with the peripheral edge of a through hole 19b of the sensor holder 19 described later, and the lower end of the detection rod 12 is regulated by the stopper ring 13 coming into contact with the main body 16a of the adjusting screw 16 described later. .

The adjusting screw 16 arranged at the lower end of the electrode holder 6 is a male screw portion 16 formed on the outer peripheral surface of the main body 16a.
It is connected to the electrode holder 6 by screwing b into the female screw portion 6c. The adjusting screw 16 has a through hole 16c through which the small diameter portion 12c of the detection rod 12 can be inserted, and a recess 16d that constitutes a spring seat of the coil spring 14 at the upper end of the main body 16a. Further, the adjusting screw 16 is provided with a flange portion 16e at the lower portion, and is provided with a concave portion 16f which is fitted to the vicinity of the flange portion 19c of the sensor holder 19 at the periphery of the through hole 16c in the lower end surface of the main body 16a.

Reference numeral 15 is a lock nut, and the lock nut 15 firmly fixes the adjusting screw 16 to the electrode holder 6. Reference numeral 23 is a water jacket.

The sensor holder 19 holds the sensor 21, and comprises an upper cylindrical portion 19a and a lower cylindrical portion 19d. The upper cylindrical portion 19a is provided with a through hole 19b through which the small diameter portion 12c of the detection rod 12 is inserted, and a flange portion 19c is formed on the outer peripheral surface of the upper cylindrical portion 19a. Also, the lower cylindrical portion 19d
Is provided with a ridge 19e for fitting the upper portion 21a of the sensor 21 on the inner peripheral surface of a substantially intermediate portion in the vertical direction.
A window portion 19f that opens outward is formed on the upper portion of 9d, and a female screw portion 19g that corresponds to the male screw portion 21b of the sensor 21 is formed on the inner peripheral surface of the lower portion of the cylindrical portion 19d.

In this sensor holder 19, the vicinity of the flange portion 19c of the upper cylindrical portion 19a is fitted into the recess 16f of the adjusting screw 16 and is fixed to the adjusting screw 16, and the cover 17 which is a two-piece body is used. Flange part 19c
Will be rotatably fixed to the lower part of the adjusting screw 16 so as to be clamped.

The sensor 21 is provided with a contact 21c that projects from the upper portion 21a and can come into contact with the lower end of the detection rod 12, and can detect two positions when the detection rod 12 moves downward. This sensor 21 has a male screw part 2
1b is screwed into the female threaded portion 19g and the upper portion 21a
The contact 21c to the window 19
It is held at the sensor holder 19 by being placed at the position of f. Reference numeral 20 is a lock nut for firmly fixing the sensor 21 to the sensor holder 19.

Next, the resistance welding machine M1 of the first embodiment will be described.
A case where the nut 31 shown in FIGS. 4 and 5 is welded to the work 30 by using will be described.

The arrangement relationship of each member corresponding to the nut 31 will be described. The screwing position of the adjusting screw 16 with respect to the electrode holder 6 is adjusted to prevent the coil spring 10 from bending.
And

Further, the length x of the guide portion 5c of the guide pin 5 protruding from the upper surface of the work 30 set on the upper surface 4a of the electrode tip 4, the stopper ring 13 and the adjusting screw 16
Gap S between the upper surface of the nut, the gap s1 between the nut 31 and the work 30 when set on the guide pin 5, the sensor contact 21
c, the gap s2 between the lower end of the detection rod 12, the total height H of the nut 31, the gap m between the upper surface of the nut 31 and the upper end of the guide portion 5c of the guide pin 5, the height h of the welded portion 31a of the nut 31, the workpiece. When the thickness t is 30, the guide collar 9
・ 11 the mutual separation distance is x−S, and x = (H−
m) + s1 and S = h + s1.

Further, the sensor 21 has a contact 21c.
However, when moving a distance of s1-s2 (this position is the arrangement position of the first position of the guide pin 5), S-s
When moving a distance of 2 (this position is the second position of the guide pin 5)
When it becomes the position of the position), the control device 1 is turned on.
Be sure to output a signal.

Furthermore, a timer is built in the control device 1, and after a certain time (T time) after the upper electrode 2 starts descending, the presence or absence of a signal from the sensor 21 causes the upper electrode 2 to operate. It is programmed so as to carry out a predetermined descending / ascending and supplying a welding current to the upper / lower electrodes 2 and 3. Specifically, the control device 1 includes the upper electrode 2
Within the time T after the start of
Only when the ON signal for position detection is input, a welding current is applied to the electrodes 2 and 3, and after the ON signal for second position detection from the sensor 21 is input, after the stabilization time of welding, the upper part The electrode 2 is controlled to rise. On the other hand, the control device 1 receives the detection ON signals of the first and second positions from the sensor 21 at substantially the same time within the time T after the upper electrode 2 starts to descend, and when the sensor 21 receives the first ON signal. When the 2-position detection ON signal is not input, welding is disabled and the upper electrode 2 is controlled to be separated from the lower electrode 3.

Then, first, the through hole 30a is inserted into the guide portion 5
c, and set the work 30 on the guide pin 5,
When a start button (not shown) of the control device 1 is pressed, a nut 31 is supplied from a nut feeder (not shown), and the through hole 3
The nut 31 is set on the guide pin 5 while the guide portion 5c is covered with 1b, and the upper electrode 2 is lowered.

At this time, if the nut 31 set on the guide pin 5 is a normal nut, the welded portion 31a of the nut 31 comes into contact with the work 30 from the set position, as shown in FIGS. Down the distance of s1.

Then, the guide pin 5, the guide collar 9,
The coil spring 10, the guide collar 11, and the detection rod 12 also decrease the distance of s1 against the biasing force of the coil spring 14, and the lower end of the detection rod 12 has the sensor contact 21.
Since the contact 21c is lowered by the distance of s1 to s2 by contacting with c, it is detected that the sensor 21 is arranged at the first position of the guide pin 5, and the first position detection ON signal is sent to the control device 1. Is output.

Then, the control unit 1 causes the sensor 21 to move the first guide pin 5 to the first position within a predetermined T time.
Since only the signal placed in the position position is input,
After confirming that the normal nut has been supplied to the welding machine M, the welding current is applied to the upper and lower electrodes 2 and 3 while pressing the upper electrode 2.

Then, the welded portion 31a of the nut 31 is melted, the nut 31 is welded to the work 30, and
Further, the nut 31 descends by a distance of h, and the guide pin 5,
Guide collar 9, coil spring 10, guide collar 11,
The detection rod 12 and the sensor contact 21c also resist the biasing force of the coil spring 14 and further move down the distance of h.

That is, the nut 31 descends by a distance of S (s1 + h) from the set position set on the guide pin 5, and the contact 21c moves from the set position to S-s.
Since the sensor 21 is lowered by the distance of 2, the sensor 21 detects that the guide pin 5 is arranged at the second position, and outputs the second position detection ON signal to the control device 1.

By the way, after the detecting rod 12 is lowered by the distance S from the position where the nut 31 is set on the guide pin 5, the stopper ring 13 is moved to the main body 1 of the adjusting screw 16.
Since it abuts on the upper surface of 6a, it is prevented from further descending.

Then, the control device 1 receives the signal from the sensor 21 arranged at the second position of the guide pin 5.
After the time for stabilizing the welding elapses, the upper electrode 2 is raised and the welding is waited for the next welding operation (see FIG. 11).

On the other hand, when the back nut 31B is supplied to the guide portion 5c of the guide pin 5 from the nut feeder (not shown), when the control device 1 lowers the upper electrode 2, the back nut 31B contacts the upper electrode 2. When pressed in contact, the state shown in FIG. 7 is obtained. At that time, since the welded portion 31a is not arranged on the work 30 side, the welded portion 31a immediately descends by the distance S within the range of T time from the initial set position. That is, since the sensor 21 outputs the signals arranged at the first and second positions of the guide pin 5 to the control device 1 substantially at the same time, the control device 1 determines that welding is impossible and outputs an abnormal signal, Along with raising the upper electrode 2, a patrol light or the like is operated so as to notify the surrounding workers of the abnormality. Therefore, after that, the operator may remove the nut 31B and restart the welding operation (see FIG. 12).

Further, if the nut is not supplied from the nut feeder (not shown), or if the nut is supplied and is out of the range of the electrodes 2 and 3, when the control device 1 lowers the upper electrode 2, FIG. As shown in, the guide portion 5c of the guide pin 5 is pushed by the upper electrode 2 and descends. At that time, the sensor 21 outputs the signals arranged at the first and second positions of the guide pin 5 to the control device 1 substantially at the same time, so the control device 1 judges that welding is not possible, and the upper electrode 2 is disconnected. Since it is raised, the worker may restart the welding work as described above (see FIG. 12).

Incidentally, at this time, even if the upper electrode 2 lowers the guide pin 5 by the distance S or more, the guide collar 9
The coil spring 10 between 11 is contracted so that the guide pin 5 can be lowered without any trouble.

Further, the nut 31 supplied from a nut feeder (not shown) does not fit into the guide pin 5 and the electrode 2
When the control device 1 lowers the upper electrode 2 when it is out of the range of 3, the upper electrode 2 comes into contact with the nut 31 and the guide pin 5 is not lowered, as shown in FIGS. Therefore, the sensor 21 has the first and second guide pins 5
Since the signal placed at the position is not output to the control device 1 within a predetermined T time, the control device 1 determines that welding is not possible and raises the upper electrode 2, so that the operator does not It is sufficient to remove 31 and restart the welding operation (see FIG. 13).

Further, when the nut 31 is supplied to the guide pin 5 without the work 30 being set (generally, in such a case, the work non-setting detection sensor is often activated to cause an abnormal stop). ), For example, if t ≧ h, the sensor 21 detects the first and second positions O
Since the N signal is output to the control device 1 substantially at the same time, the control device 1 can output the abnormal signal to raise the upper electrode 2.

As a welding member to be welded to the work 30, as shown in FIGS. 14 and 15, the cylindrical pilot 3 is provided at the periphery of the through hole 32b on the rear surface side having the welded portion 32a.
Similarly, in the case of the hexagon nut 32 having 2c,
With the normal nut 32, as shown in FIG. 16, when the upper electrode 2 descends by a distance of s1, the welding portion 32a once contacts the work 30 and a welding current is applied to the upper and lower electrodes 2 and 3. If the welded portion 32a is melted by this, the nut 32 is lowered again by the height h of the welded portion 32, so that the guide pin 5
The sensor 21 can detect the moving distance of the
Similar to 1, it can be welded.

Then, when the nut 32 is supplied in an abnormal state like the back nut 32B, etc., as shown in FIGS.
As shown in, when the signal is not output from the sensor 21 within a predetermined T time, or the signals arranged at the first position and the second position of the guide pin 5 are instantaneously output to the control device 1. The control device 1 determines that the welding is impossible and raises the upper electrode 2.

Therefore, in the resistance welding machine M of the first embodiment, a predetermined guide on the lower electrode 3 side depending on the presence / absence of the welded portions 31a / 32a of the nuts 31/32 which are always present on the work 30 side under normal conditions. Depending on the descending distance of pin 5,
This is for judging whether the supply state of the nuts 31 and 32 is normal or abnormal, and unlike the conventional welding machine, it is not necessary to prepare an auxiliary electrode corresponding to the nut or an upper electrode having a recess,
Even if the welded portion 32a does not have a shape projecting from the outer periphery of the nut 32 main body, the nuts 31 and 32 at the normal arrangement position are provided.
Only the can be easily welded to the work piece.

In the first embodiment, the rising end and the falling end are provided between the guide pin 5 and the sensor 21 by the stopper ring 1.
3 and the rod stopper 18, and the detection rod 12 is biased upward by the coil spring 14 having a predetermined biasing force.
Since a gap D (D> x + t) is provided between the guide pin 5 and the guide pin 5, and the guide collar 9 capable of descending a distance of the height x + t protruding from the electrode chip upper surface 4a of the guide pin 5 is interposed, Even if the guide pin 5 is pushed down by the upper electrode 2 and moves down abnormally beyond the normal welding work, the sensor 21 is not damaged.

By the way, even if the above configuration is not adopted, the contact 21c is brought into direct contact with the guide pin 5 and a spring or the like is used so as to lower the sensor 21 when a pressing force of a predetermined amount or more acts on the contact 21c. If it is held by the electrode holder 6, the sensor 21 can be prevented from being damaged without using the detection rod 12 or the like.

Similarly, if the upper electrode 2 is constructed so that it can be raised instantaneously, the contact 21c of the sensor 21 can be directly brought into contact with the guide pin 5 without providing the detection rod 12 and the like.

Even if the sensor 21 is not arranged in a contact type below the lower end of the detection rod 12, the first position of the detection rod 12 is
・ When moving to the second position, from the horizontal direction,
The same control can be performed by disposing a sensor such as a proximity switch or a photoelectric switch so that the detection can be performed by contact or non-contact.

Further, in the first embodiment, the repair when the upper surface 4a of the welding tip 4 is worn or damaged by the welding work will be described. First, the lock nut 15 will be described.
Is loosened, the adjusting screw 16 is rotated and pulled out from the electrode holder 6, and the guide portion 5c of the guide pin 5 is made lower than the upper surface 4a, the upper surface 4a can be corrected.

When the upper surface 4a is modified or the electrode tip 4 is replaced, or when the type of nut or the plate thickness of the work is changed, the adjusting screw 16 is loosened a little to guide the guide pin 5. The portion 5c is the electrode chip upper surface 4a.
From above, the work 30 or a test piece having the same plate thickness or the like is set so as to protrude upward by a dimension approximately equal to the thickness t of the work 30, and the upper electrode 2 is lowered until it abuts the upper surface 4a.

Thereafter, while the adjusting screw 16 is tightened, the gap x-S between the guide collars 9 and 11 is set to 0, and the gap S between the guide collar 11 and the stopper ring 13 is set to 0, and the adjusting screw 16 is locked. By fixing with 15 and raising the upper electrode 2, the guide pin 5 and the detection rod 12
Can be arranged at a predetermined position (relatively the same position as the original position) from the upper surface 4a of the electrode chip 4. By the way,
At this time, when the electrode tip 4 is thinned by grinding the upper surface 4a of the electrode tip 4 or the like, the flange portion 5 of the guide pin 5
The distance between b and the sleeve portion 4c of the electrode tip 4 is increased, but since the guide pin 5 is prevented from rattling by the coil spring 7, no trouble occurs. Further, when the adjusting screw 16 is rotated, the sensor holder 19 is connected to the adjusting screw 16 in a freely rotating manner, so that there is no fear of affecting the sensor 21.

Further, in the first embodiment, the square nut 31 is used.
Although the case where the hexagonal nut 32 and the hexagonal nut 32 are welded to the work 30 has been shown, if the projecting welded portion (projection welded portion) is provided only on the back surface side to be welded, the work piece is formed using the back surface side. The present invention can be applied to the case of welding to, and the welding member is not limited to a nut or the like, and a ring-shaped or hollow-shaped member such as a washer may be used.

Furthermore, depending on the type of the existing resistance welding machine, there are some that cannot be externally input / output such as an interlock signal depending on the control circuit. In such cases,
The lower electrode of the existing welding machine is changed to the lower electrode 3 of the embodiment, and when welding is not possible, the power of the existing welding machine is turned off instead of raising the upper electrode 2 as shown in FIGS. The present invention can be carried out by incorporating a control device for stopping the welding operation by the welding.

That is, the control unit is provided with a timer M1 which is substantially synchronized with the initial pressurization time of the existing welding machine, and the first of the sensor 21.
-Built-in timer M2, which serves as a reference time for confirming the operation of the second position detection.

The timer M1 operates in synchronization with the lowering signal of the upper electrode 2 of the existing welding machine, and is turned off at a preset time before the initial pressurization time of the existing welding machine is timed up.
To be done.

In the timer M2, the upper electrode 2 of the existing welding machine descends, the nut 31 and the guide pin 5 are depressed, and the contact 21c of the sensor 21 is detected at the first position.
Operates at the same time when a signal is detected, and after a certain set time, O
FF is done. This set time is set by the welding energization interlock time of the existing welder.

In addition, in the case of an abnormality in the supply of the nut 31 and the work 30, this control device outputs an abnormality signal to turn off the power of the existing welding machine and informs the occurrence of the abnormality with a buzzer or the like. .

Further, regarding the specific operation of this control device, first, when the work 30 and the nut 31 are set on the guide pin 5 of the electrode tip 4 on the lower electrode 3 side, the existing welding machine operates. , The upper electrode 2 descends. Then, at the same time, the timer M1 of the control device is activated.

Then, when the upper electrode 2 pushes down the guide pin 5 together with the nut 31 by s1, the contact 21c of the sensor 21 outputs the first position detection ON signal to the control device. Then, at the same time, the timer M2 starts operating.

Within the set time of this timer M2, the sensor 2
If 1 does not output the second position detection ON signal to the control device, the control device determines that the supply of the nut 31 is normal, does not output the abnormal signal, and the existing welding machine side continues the welding operation, Complete the welding operation (see Figure 21).

Then, within the set time of the timer M2,
When the sensor 21 outputs the second position detection ON signal to the control device, the control device determines that there is an abnormality (back nut / no nut / no work) supply, outputs an abnormality signal, and supplies power to the existing welding machine. Is turned off, welding is stopped, and a buzzer or the like is operated (see FIG. 22).

If the sensor 21 does not output the first and second position detection ON signals before the timer M1 times out, the control device judges that the abnormality is as shown in FIGS. Is output, the power of the existing welding machine is turned off, and the buzzer or the like is operated.

Next, the resistance welding machine M2 of the second embodiment shown in FIGS. 23 and 24 will be described. In the resistance welding machine M2 of the second embodiment, like the resistance welding machine M1 of the first embodiment, first, the work 30 is set on the lower electrode 3, and then the nut 31 is set on the upper surface of the work 30. Contrary to the one used for welding, as shown in FIG.
First, the nut 31 is set on the lower electrode 3, the work 30 is set on the upper surface of the nut 31, and is used for welding, which is used when the work 30 is U-shaped or the like. Is.

In the resistance welding machine M2 of the second embodiment, the length of the guide portion 5c of the guide pin 5 is different from that of the first embodiment, and the same parts as those of the first embodiment are provided. Is configured. The description of the same members as those in the first embodiment will be omitted.

The length of the guide portion 5c of the guide pin 5 of the second embodiment is longer than the total height H of the nut 31, and the total height H of the nut 31 and the thickness t of the work 30.
The length is shortened by the dimension n from the length obtained by adding and.

The arrangement relationship of each member corresponding to the nut 31 of the second embodiment will be described. At the set position where the nut 31 and the work 30 are set, the guide pin 5 guides from the upper surface 4a of the electrode tip 4 to the guide pin 5. The length y to the upper end of the portion 5c, the gap S between the stopper ring 13 and the upper surface of the adjusting screw 16, the gap s1 between the nut 31 and the electrode tip 4 at the set position, the sensor contact 21c and the lower end of the detection rod 12. The gap s2, the total height H of the nut 31, the gap n between the upper surface of the work 30 and the upper end of the guide portion 5c of the guide pin 5 at the set position, the height h of the welded portion 31a of the nut 31, the thickness t of the work 30. , And the mutual separation distance of the guide collars 9 and 11 is y-S, y = s1 + H + t
It is adjusted so that the relationship of −n, S = s1 + h−n, n <t, n <h, and t ≧ h holds. Note that normally, n≈t /
It is 3.

Further, the sensor 21 has a contact 21c.
However, when moving the distance of s1 (this position is the guide pin 5
Of the second position) and when the distance S-s2 is moved (this position is the second-position position of the moved guide pin 5 for S = s1 + hn). Then, an ON signal is output to the control device 1. Further, in the same manner as in the first embodiment, the control device 1 has a built-in timer, and when only the first position detection ON signal from the sensor 21 is input within a predetermined time after the upper electrode 2 starts to descend. Only, welding current is passed to the electrodes 2 and 3, and the second position detection from the sensor 21 is turned on.
After the input of the signal, the upper electrode 2 is controlled to rise after the stabilization time of welding has passed. On the other hand, when the first and second position detection ON signals of the sensor 21 are not input within a predetermined time when the upper electrode 2 starts descending, and the sensor 2
When the first and second position detection ON signals from 1 are input substantially at the same time, the control device 1 determines that welding is not possible and controls the upper electrode 2 to separate from the lower electrode 3.

Then, in this resistance welding machine M2, when the nut 31 and the work 30 are set on the guide pin 5 and the set nut 31 is a normal nut when the upper electrode 2 is lowered, as shown in FIGS. As shown in FIG. 3, the nut 31 is pushed by the upper electrode 2, the nut 31 comes into contact with the upper surface 4a of the electrode tip, the guide pin 5 descends by a distance of s1, and the sensor 21 outputs the first position detection ON signal within a predetermined time. In order to output only the current to the control device 1, the control device 1 applies a welding current to the upper and lower electrodes 2 and 3. After that, the welded part 31
If a is melted, the upper end of the guide portion 5c of the guide pin 5 is pushed by the upper electrode 2 and further descends by hn (s1 + hn minutes from the set position). The second position detection ON signal is output to the control device 1, and the control device 1 outputs the nut 31 as in the first embodiment.
After the welding of the work 30 and the work 30 is stabilized, the upper electrode 2 is lifted to be in a standby state for the next welding work.

When the back nut 31B is set, as shown in FIG. 26, when the upper electrode 2 descends and the nut 31B comes into contact with the upper surface 4a of the electrode tip, the guide pin 5 moves to the y- (H + t), that is, s1 + H + t-
Since n- (H + t) = s1-n, the sensor 21 does not output the first position detection ON signal, and the control device 1 determines that welding is not possible and the abnormal signal is generated. Is output to raise the upper electrode 2.

Further, when the upper electrode 2 descends in a state where the nut 31 is not supplied, as shown in FIG. 27, the guide pin 5 is instantaneously large and descends by yt, and yt.
= S1 + H-n> s1 + h-n = S, the sensor 21 outputs the first and second position detection ON signals substantially at the same time, and the control device 1 determines that welding is impossible and outputs an abnormal signal, The upper electrode 2 will be raised.

Further, when the upper electrode 2 descends with the work 30 not set, as shown in FIG. 28, the guide pin 5 is moved to y-H, that is, s1 + t-n.
By a minute, t ≧ h, and s1 + t−n ≧ s1 + h−n
= S, the sensor 21 outputs the first and second position detection ON signals substantially at the same time, and the control device 1 determines that welding is not possible, outputs an abnormal signal, and raises the upper electrode 2. Become.

Therefore, the resistance welding machine M2 of the second embodiment also has the same effect as that of the first embodiment. In addition, in the second embodiment as well, a welding member such as the hexagon nut 32 can be used, and it can be incorporated into an existing resistance welding machine.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing upper and lower electrodes of a resistance welding machine according to a first embodiment of the present invention.

FIG. 2 is an enlarged partial sectional view of upper and lower electrodes of the same embodiment.

FIG. 3 is an enlarged partial sectional view of a lower electrode of the same example.

FIG. 4 is a plan view of a nut to be welded in the same example.

FIG. 5 is a sectional view of the nut.

FIG. 6 is a view showing a time when a normal nut is welded in the example.

FIG. 7 is a diagram showing the operation of the everted nut in the embodiment.

FIG. 8 is a view showing an operating time when the nut is removed in the embodiment.

FIG. 9 is a view showing a state in which the nut is removed and the nut is removed in another embodiment in the embodiment.

FIG. 10 is a view showing a time of operation in still another mode in which the nut is removed in the example.

FIG. 11 is a time chart diagram showing a time when a normal nut is welded in the example.

FIG. 12 is a time chart diagram showing an operation at the time when the nut of the inside out and the nut are removed in the embodiment.

FIG. 13 is a time chart diagram showing a time of operation in another mode in which the nut is removed in the example.

FIG. 14 is a plan view of another nut to be welded in the example.

FIG. 15 is a sectional view of the nut.

FIG. 16 is a view showing another normal nut being welded in the example.

FIG. 17 is a diagram showing the operation of the everted nut in the embodiment.

FIG. 18 is a view showing an operating time when the nut is removed in the example.

FIG. 19 is a view showing a state in which the nut is removed in another mode of operation in the same Example.

FIG. 20 is a view showing still another mode of operation in which the nut is removed in the same example.

FIG. 21 is a time chart diagram showing a time when a normal nut is welded in a modified example of the embodiment.

FIG. 22 is a time chart diagram showing an operation time when the nut of the inside out and the nut are removed in the modified example of the embodiment.

FIG. 23 is an enlarged partial cross-sectional view of the upper and lower electrodes of the second embodiment.

FIG. 24 is an enlarged partial cross-sectional view of a lower electrode of the same example.

FIG. 25 is a view showing a time when a normal nut is welded in the example.

FIG. 26 is a view showing the operation of the everted nut in the example.

FIG. 27 is a view showing an operating time when the nut is not set in the embodiment.

FIG. 28 is a diagram showing an operation time when the work is not set in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Control device, 2 ... Upper electrode, 3 ... Lower electrode, 4 ... Electrode tip, 5 ... Guide pin, 5b ... Step part, 5c ... Guide part, 6 ... Electrode holder, 21 ... Sensor, 30 ... Work piece, 30a ... Through hole, 31/32 ... (welding member) nut, 31a / 32a ... (Projection) welded part, 31b / 32b ... through hole, M1 / M2 ... Resistance welding machine.

Claims (2)

[Claims] 1. A welding member comprising an upper electrode and a lower electrode, a work piece set on a guide pin of the lower electrode, having a projection welding portion on the back surface side and a through hole penetrating through the front surface and the back surface on a top surface of the work piece. A resistance welding machine that sets from the back side, pressurizes with the upper electrode from the front side of the welding member, and resistance-welds the welding member to the workpiece, wherein the lower electrode is a welding site of the workpiece. An electrode tip capable of abutting the lower surface of the electrode holder, and a cylindrical electrode holder which is fixed to the resistance welding machine main body by holding the electrode tip at the upper end and movably arranges the guide pin downward at the inner peripheral portion of the upper portion. A sensor that can detect movement of the guide pin below the guide pin, the guide pin passing through the electrode tip and protruding upward from the electrode tip. A guide part that can be inserted into the through hole of the welding member and has a length shorter than the length of the through hole of the welding member, and a step part that can abut the peripheral edge of the through hole of the welding member at the lower part of the guide part. The sensor projects the welding member from a set position in which the guide member is inserted into the through hole and the step portion is brought into contact with the peripheral edge of the through hole to set the welding member on the guide pin. When the welded portion is moved to the position of the first position for contacting the work,
After that, during welding, when the projection welded portion is melted and the welding member is moved to the position of the second position where the workpiece is welded, it is possible to detect a two-step movement, and the control device detects the sensor. When the detection signals of the first and second positions are detected substantially at the same time,
The resistance welding machine is characterized in that when a two-position detection signal is not input, welding is prohibited, an abnormal signal is output, and welding work is stopped. 2. A welding member comprising an upper electrode and a lower electrode, a projection welding portion on the back surface side of the guide pin of the lower electrode, and a through hole penetrating the front and back surfaces, and the back surface side being the upper surface. Set it to the side, and then
A work piece having a through hole into which the guide pin can be inserted is set on the upper surface of the welding member, pressure is applied from the upper surface side of the work piece by the upper electrode, and resistance for welding the welding member to the work piece is performed. A welding machine, wherein the lower electrode is fixed to the body of the resistance welding machine by holding the electrode tip capable of abutting the lower surface of the welding member on the upper end, and the guide pin at the upper inner peripheral portion. And a sensor capable of detecting movement of the guide pin below the guide pin, wherein the guide pin is inserted through the electrode tip and It can be inserted into the through hole of the welding member by projecting upward from the electrode tip, longer than the total height of the welding member, and shorter than the total length of the welding member and the thickness of the workpiece. The guide part, and a step part that can abut against the peripheral edge of the through hole of the welding member in the lower part of the guide part, and the sensor causes the through hole of the welding member to be fitted in the guide part and the welding. The welding member is set on the guide pin by abutting the stepped portion on the periphery of the through hole of the member, and further, the through hole of the workpiece is inserted into the guide portion on the upper surface of the welding member to insert the workpiece. From the set position set, when the surface side of the welding member is moved to the position of the first position where it contacts the upper surface of the electrode tip, and thereafter, during the welding, the projection welded portion is melted and the welding member is the work piece. Second welded to
It is possible to detect movement in two steps, that is, when the control device detects the detection signals of the first and second positions of the sensor at substantially the same time, and when the control device detects the first and second positions of the sensor.
The resistance welding machine is characterized in that when a two-position detection signal is not input, welding is prohibited, an abnormal signal is output, and welding work is stopped.